JP6857184B2 - Purification process for hydrophilic organic solvents - Google Patents

Description

The present invention generally relates to methods for removing contaminants from hydrophilic organic solvents. Specifically, the present invention relates to a method for removing metal and non-metal ionic contaminants from a hydrophilic organic solvent using a mixed bed of ion exchange resins.

Introduction Pure solvents free of ionic pollutants are required for many industrial purposes such as the manufacture of pharmaceuticals and electronic materials. In particular, organic solvents with fairly low levels of metal ionic contaminants are required in the semiconductor manufacturing process because contamination by metal ions adversely affects the performance of semiconductor devices. For example, some hydrophilic organic solvents containing alcohols and ethers such as propylene glycol methyl ether (PGME) are useful in semiconductor manufacturing processes. Therefore, when hydrophilic organic solvents are used in semiconductor manufacturing processes, it would be desirable for such solvents to have fairly low levels of metal ionic contaminants.

Ion exchange resins have been used for the purification of water by removing ionic contaminants from the water. In recent years, such ion exchange techniques have been applied to the purification of organic solvents used to produce electronic materials. However, the behavior of ionic pollutants in organic solvents is believed to be different from that in water due to differences in polarity, so techniques for water purification using ion exchange resins are Generally not expected to be suitable for use directly in organic solvents.

Conventional methods for removing metal ions from organic solvents have been disclosed. U.S. Pat. No. 7,329,354 discloses a system for the purification of organic solvents with ion exchange resins. Japanese Patent No. JP5,096,907B is for removing anionic impurities from the ester by a weak anion exchange resin or anion exchange resin in which OH groups in the anion exchange resin are capped and inactivated. The method of is disclosed. US Pat. No. 6,123,850 is a method for purifying a substantially anhydrous organic liquid with a cation exchange resin based on a polystyrene divinylbenzene copolymer having a considerably high content of divinylbenzene (50-60%). Is disclosed. JP2009 / 057286A discloses a method for removing cationic impurities from alcohols with a cationic exchange resin having a crosslink of 8% by weight or less. US Pat. No. 5,518,628 uses a mixed bed ion exchange resin in which the strong base anion exchange resin of the mixed bed ion exchange resin is modified with an ammonium salt of a weak organic acid, and ionic contamination from an organic solution. It discloses a method for removing substances.

However, these processes are inadequate for removing ionic contaminants from organic solvents used in applications that require fairly high levels of purity. Therefore, a new process for removing high levels of ionic contaminants from hydrophilic organic solvents is desired.

The present invention provides a process for removing ionic contaminants from hydrophilic organic solvents such that the solvent has very low levels of ionic contaminants. In some embodiments, the process is a mixed bed of gel-type strong acid cationic ion exchange resins having a specific water retention capacity (40-55% by weight) and ion exchange resins containing gel-type anionic ion exchange resins. To use. By using a mixed bed of ion exchange resins, it is possible to obtain an extremely pure hydrophilic organic solvent with less metal and non-metal ionic contaminants.

Therefore, one aspect of the present invention relates to a method for removing an ionic contaminant from a hydrophilic organic solvent, and the present method uses a hydrophilic organic solvent, a cationic ion exchange resin and an anionic ion exchange resin. Including contacting with a mixed bed of an ion exchange resin containing, (a) the cation exchange resin is a hydrogen (H) type strong acid cation exchange resin having a water retention capacity of 40 to 55% by weight. (B) Both the cationic ion exchange resin and the anionic ion exchange resin ^{have a porosity of 0.001 to 0.1 cm 3} / g, an average pore size of 0.001 to 1.7 nm, and 0. It has a BET surface area of .001 to 10 m ^{2 / g.}

Another aspect of the present invention is according to the method described herein, wherein the concentrations of Na, K, Ca, Al, Fe, Ni, Zn, Cu, Cr, and Sn are each 0.1 ppb or less. Regarding the obtained hydrophilic organic solvent.

In another aspect, the present invention relates to a method for removing an ionic contaminant from a hydrophilic organic solvent, wherein the method comprises (i) a cationic ion exchange resin and an anionic ion exchange resin. In the step of preparing a mixed bed of resins, (a) the cationic ion exchange resin is a hydrogen (H) type strong acid cationic ion exchange resin having a water retention capacity of 40 to 55% by weight, and (b). ) Both the cationic ion exchange resin and the anionic ion exchange resin ^{have a porosity of 0.001 to 0.1 cm 3} / g, an average pore size of 0.001 to 1.7 nm, and 0.001 to 10 m. ^It comprises a step of preparing having a BET surface area of 2 / g and (ii) a step of contacting a hydrophilic organic solvent with a mixed bed of ion exchange resins.
The present specification also discloses inventions of the following aspects.
[1]
A method for removing ionic contaminants from a hydrophilic organic solvent, wherein the method is:
Including contacting the hydrophilic organic solvent with a mixed bed of an ion exchange resin containing a cationic ion exchange resin and an anionic ion exchange resin.
(A) The cationic ion exchange resin is a hydrogen (H) type strong acid cationic ion exchange resin having a water retention capacity of 40 to 55% by weight.
(B) Both the cationic ion exchange resin and the anionic ion exchange resin ^{have a porosity of 0.001 to 0.1 cm 3} / g, an average pore size of 0.001 to 1.7 nm, and 0. A method having a BET surface area of 001 to 10 m ^{2 / g.}
[2]
The mixed bed of the ion exchange resin is described by the following method:
The mixed bed of the ion exchange resin is washed with 25 bed volumes (BV) of ultrapure water for 24 hours, and then the total organic carbon of the ultrapure water is analyzed. The method according to the above [1].
[3]
The contents of Na, K, Ca, Al, Fe, Ni, Zn, Cu, Cr, and Sn in the H-type strongly cationic ion exchange resin and the anionic ion exchange resin are the ion exchanges, respectively. The method according to the above [1], wherein the dry weight of the resin is 10 mg / kg or less as a reference.
[4]
The concentrations of Na, K, Ca, Al, Fe, Ni, Zn, Cu, Cr, and Sn in the hydrophilic organic solvent after contact with the mixed bed of the ion exchange resin are 0.1 ppb or less, respectively. The hydrophilic organic solvent obtained by the method according to the above [1].
[5]
A method for removing ionic contaminants from hydrophilic organic solvents.
(I) A step of preparing mixed bed ions of an exchange resin containing a hydrogen (H) type strongly cationic ion exchange resin and a strongly anionic ion exchange resin.
(A) The cationic ion exchange resin has a water retention capacity of 40 to 55% by weight.
(B) Both the cationic ion exchange resin and the anionic ion exchange resin ^{have a porosity of 0.001 to 0.1 cm 3} / g, an average pore size of 0.001 to 1.7 nm, and 0. With a step of preparation, having a BET surface area of 001 to 10 m ^{2 / g,}
(Ii) A method comprising contacting a hydrophilic organic solvent with the mixed bed of the ion exchange resin.
[6]
The method further comprises rinsing (iii) the mixed bed of the ion exchange resin with the hydrophilic organic solvent in a volume of 30-50 bed volumes (BV) at a flow rate of 1-50 BV / hour, step (iii). The method according to [5] above, which is carried out between steps (i) and (ii).

As used throughout this specification, the abbreviations given below have the following meanings, unless the context clearly indicates that they have other meanings: g = gram, mg = milligram, L = liter, mL. = Milliliter, ppm = one millionth, ppb = one billionth, m = meter, mm = millimeter, cm = centimeter, min. = Minutes, s = seconds, hr. = Time, ° C = C degrees = Celsius, vol% = volume percent, wt% = weight percent.

The methods of the present invention are generally applicable to hydrophilic organic solvents. Specifically, the method is useful for water-miscible protic solvents such as hydrophilic organic solvents. Examples of hydrophilic organic solvents include, but are not limited to, alcohols, ethers, and mixtures thereof. Examples of alcohols for which the methods of the invention can be used include methanol, ethanol, propanol, i-propanol, and mixtures thereof. Examples of ethers which may be used the method of the present invention, propylene glycol monomethyl - methyl ether (PGME), dipropylene glycol mono - methylation ether, diethylene glycol monoethyl ether, diethylene glycol mono - butyl ether, and mixtures thereof Can be mentioned.

The method of the present invention uses a mixed bed of ion exchange resins. A mixed bed of ion exchange resins refers to a mixture of cation exchange resins and anion exchange resins. The cationic ion exchange resin used in the mixed bed of the ion exchange resin is a hydrogen (H) type strong acid cationic ion exchange resin, and these are cationic exchange groups bonded to the polymer molecules forming the resin beads. Is. An example of such an H-type strong acid cation exchange group is sulfonic acid. H-type strong acid cation exchange groups, such as sulfonic acids, release ^{protons (H +) in exchange for cation impurities in hydrophilic organic solvents.} Resin beads of cation exchange resins are usually spherical polymers formed from compositions containing styrene and divinylbenzene. Thus, in some embodiments, the H-strong acid cation exchange resin comprises a sulfonic acid attached to a polymer molecule formed from a composition comprising styrene and divinylbenzene.

The water retention capacity of the cationic ion exchange resin used in the mixed bed of the ion exchange resin is 40 to 55% by weight. The water retention capacity refers to the amount of water in the ion exchange resin when the ion exchange resin is in a water-containing state (swells with water). Water retention is a number of factors, primarily the chemical structure of the base resin (styrene or acrylic), the degree of cross-linking of the base resin, the morphology of the base resin beads (gel or MR), and the ion exchange beads. It varies depending on the size and the number of cation exchange groups. In some preferred embodiments, the water retention capacity of the cationic ion exchange resin is 45-50% by weight in the water-containing state. As used herein, water retention is calculated by the following method: the water content in a cation exchange resin is calculated by comparing the weight of the ion exchange resin before and after drying. The drying conditions are 105 ° C. for 15 hours under a vacuum of 20 mmHg, followed by cooling in a desiccator for 2 hours. Using the reduced weight after drying based on the hydrous ion exchange resin, the water retention capacity is determined based on the following formula:
Water retention capacity = (weight of hydrous ion exchange resin-weight of ion exchange resin after drying) x 100 / weight of hydrous ion exchange resin.

The anion exchange resin used in the mixed bed of the ion exchange resin is preferably a strong base anion exchange resin. The anion exchange resin has an anion exchange group bonded to the resin beads. In some embodiments, the strong base anionic ion exchange resin has a trimethylammonium group (called type I) or a dimethylethanolammonium group (type II) that binds to the polymer molecules that form the anionic ion exchange resin. Including. ^{Strong base anionic ion exchange resins release hydroxyl ions (OH −} ) in exchange for anionic contaminants in hydrophilic organic solvents. Resin beads of anionic ion exchange resins are also usually spherical polymers formed from compositions containing styrene and divinylbenzene. Thus, in some embodiments, the strong base anion exchange resin comprises a trimethylammonium group and / or a dimethylethanolammonium group on resin beads formed from a composition comprising styrene and divinylbenzene. The water retention capacity of the anionic ion exchange resin is not particularly limited, but in some preferred embodiments, the water retention capacity is 55 to 65% by weight as measured as described above.

The inventors of the present invention have shown that a mixed bed of ion exchange resins described herein can remove metals more effectively than a single cation bed, and that certain cationic ions. A mixed bed of such ion exchange resins incorporating an exchange resin (ie, an H-type strong acid cationic ion exchange resin having a water retention capacity of 40 to 55% by weight) is an extremely pure hydrophilic organic solvent with less ionic contaminants. I found that it could provide.

As described above, the H-type strong acid cation exchange group releases a ^{proton (H +) in exchange for a cationic impurity in a hydrophilic organic solvent.} The inventors of the present invention have discovered that an H-type strong acid cationic ion exchange resin having a water retention capacity of 40 to 55% by weight has the highest ion exchange capacity among hydrophilic organic solvents. When the ion exchange resin swells in an organic solvent, a larger amount of hydrophilic solvent can penetrate inside the resin beads due to less steric hindrance. As a result, the ion exchange group located inside the bead can also contribute to the ion exchange reaction, so that the frequency of the ion exchange reaction increases. In contrast, the high density resin reduces the permeation of the solvent and only the surface ion exchange sites located on the surface of the resin beads contribute to the ion exchange reaction. On the other hand, the strong base anionic ion exchange resin used in the mixed bed ^{releases hydroxyl ions (OH −} ) in exchange for anionic impurities. The released protons and hydroxyl ions _{form water (H 2} O) in a hydrophilic organic solvent. Since the hydrophilic organic solvent has a strong affinity for water, the formed water is mixed with the hydrophilic organic solvent, and as a result, the water is removed from the vicinity of the mixed bed of the ion exchange resin. In the presence of protons, the cation exchange reaction does not proceed according to the theory of equilibrium reaction. By using a mixed bed of strong acid cation exchange resin and strong base anion exchange resin, protons are removed more effectively as water, and as a result, more ionic impurities are in the mixed bed of the ion exchange resin. Comes to bond with the ion exchange resin.

Both the cationic ion exchange resin and the anionic ion exchange resin are gel-type resins in the embodiment of the present invention. As used herein and generally understood in the field of ion exchange resins, gel-type resins have very low porosity ( ^{less than 0.1 cm 3} / g) and a small average pore size (1.7 nm). Less than) and a resin with a low BET surface area ( ^{less than 10 m 2 / g).} Porosity, average pore size, and BET surface area can be measured by the nitrogen adsorption method set forth in ISO 15901-2. Such an ion exchange resin is different from a macroporous ion exchange resin having a macronet structure (MR type ion exchange resin) and a macropore diameter clearly larger than the porosity of the gel type ion exchange resin.

Gel-type ion exchange resins are preferred for use in the present invention, for several reasons: (1) Gel-type ion exchange resins are typical commercially available macroporous designs designed for high morphological stability. Alternatively, since it has less cross-linking than the macro-reticulated (MR) type ion exchange resin, it easily swells with a hydrophilic organic solvent, and (2) the ionic impurities contained in the gel type ion exchange resin are MR type ion exchange. Because it is generally less than the ionic impurities contained in the resin. The ion exchange resin and resin used in the mixed bed of ion exchange resins preferably have a water retention capacity of 40 to 55% by weight. For resins with high water retention (eg, greater than 55% by weight), the risk of organic matter leaching out of the ion exchange resin is higher. For resins with low water retention (eg, less than 40% by weight), it is difficult to rinse off contaminants from the ion exchange resin using typical rinsing procedures, and the activity of the ion exchange groups is hydrophilic organic. Low due to high steric hindrance in solvent.

The ratio of the cation exchange resin to the anion exchange resin in the mixed bed of the ion exchange resin is generally 1: 9 to 9: 1 in the equivalent ratio of the ion exchange groups in some embodiments. Preferably, the ratio is 2: 8-8: 2.

The cation exchange resin and / or the anion exchange resin may contain metal impurities resulting from the manufacturing process thereof. Such metal impurities come out of the resin and cause metal ion contamination in the treated solvent. Without being bound by any particular theory, we found that such leached metal impurities were contained in the ion exchange resin as reaction by-products or unreacted / uncrosslinked products of the resin. It is considered to be associated with low molecular weight organic compounds. Such metal-organic compound complexes are more easily dissolved in organic solvents, so that the organic compounds carry metal impurities into the organic solvent. Therefore, the inventors should minimize the amount of metal impurities and / or elution species of low molecular weight organic compounds in the ion exchange resin in order to reduce the possibility of ion contamination in the solvent being treated. Is desirable.

Examples of the metal impurities contained in the ion exchange resin include Na, K, Ca, Al, Fe, Ni, Zn, Cu, Sn, and Cr. In order to prevent metal ion contamination of the ion exchange resin, the content of these individual metal impurities in the ion exchange resin used in some embodiments of the present invention is based on the dry weight of the ion exchange resin. , Each is preferably 10 mg / Kg or less. More preferably, the content of these metal ions is 5 mg / Kg or less based on the dry weight of the ion exchange resin. The metal content can be analyzed by ICP-MS after ashing the resin sample (ie, the ion exchange resin is burned, the residual ash is dissolved in hydrochloric acid aqueous solution, and the concentration of metal ions by ICP-MS. Analyze).

The content of the elution species of the low molecular weight organic compound contained in the ion exchange resin can be evaluated by the following method. First, ultrapure water was continuously flowed into an ion exchange resin column at 25 BV / hour, and then after 24 hours of pouring, the inflow ultrapure water (referred to as UPW) and the outflow UPW TOC (total organic carbon). Measure the value. Next, the difference (or delta (Δ) TOC value) is calculated from the two TOC values. The ΔTOC value is calculated by subtracting the inflow TOC value from the outflow TOC value. In some embodiments of the present invention, the ΔTOC value measured by the above method is preferably 10 ppb or less. More preferably, the ΔTOC value is 5 ppb or less. TOCs can be analyzed by commercially available TOC analyzers using techniques known to those of skill in the art.

The cation exchange resin and the anion exchange resin originally contain water (swell with water in an equilibrium state with water). In the present invention, the water content in the cation exchange resin and the anion exchange resin is reduced to 5% by weight or less, respectively (that is, for each resin) before use. Preferably, the water content in the cation exchange resin and the anion exchange resin is 3% by weight or less in each resin. By starting the resin bed with a dry resin, the solventization time of the ion exchange resin can be saved and the solvent volume required to replace the water can be minimized. To reduce the water content, the cation exchange resin and the anion exchange resin can be dried prior to contact with the hydrolyzable organic solvent. The drying equipment and conditions for drying the ion exchange resin, such as temperature, time, and pressure, can be selected using techniques known to those of skill in the art. For example, the ion exchange resin can be heated in an oven at 60-120 ° C. for 1-48 hours under reduced pressure conditions. The water content can be calculated by comparing the weights of the ion exchange resins before and after heating in a vacuum oven of less than 20 mmHg at 105 ° C. for 15 hours and then cooling in a desiccator for 2 hours.

When contacting the hydrophilic organic solvent with the mixed bed of the ion exchange resin, any known method for contacting the liquid with the ion exchange resin can be used. For example, the mixed bed ion exchange resin can be packed in the column and the solvent can be injected from the top of the column through the mixed bed ion exchange resin. The flow rate of the solvent can be 1-100 BV / hour, preferably 1-50 BV / hour. As used herein, "BV" means the floor volume and refers to the amount of liquid in contact with the hydrous wet mixed bed ion exchange resin of the same volume. For example, when using 120 ml of a hydrous wet mixed bed ion exchange resin, 1 BV means that 120 ml of the hydrophilic organic solvent comes into contact with the mixed bed ion exchange resin. "BV / hour" was calculated by dividing the flow rate (mL / hour) by the floor volume (mL).

The temperature during contact of the hydrophilic organic solvent with the mixed bed ion exchange resin can be 0 to 100 ° C., preferably 10 to 60 ° C., more preferably 20 to 40 ° C. in various embodiments.

The resulting hydrophilic organic solvent contains fairly low levels of metal and non-metal ionic contaminants. Examples of the pollutant include Na, K, Ca, Al, Fe, Ni, Zn, Cu, Sn, and Cr. The concentration of these contaminants can be 0.1 ppb or less, respectively, in various embodiments. Therefore, the hydrophilic organic solvents obtained using the methods of the present invention are used in applications that require fairly high levels of pure solvent, such as for the production of pharmaceuticals and electronic materials, and especially for use in semiconductor manufacturing processes. Can be useful.

Hereinafter, some embodiments of the present invention will be described in detail in the following examples.

The following ion exchange resins were used.

[table]

[table]

[table]

Comparative Example 1: Strong cation exchange resin DOWNEX ™ MONOSPERE ™ 650 C UPW
120 mL (94 g) of DOWNEX ™ MONOSPER ™ 650 C UPW (MS650C UPW, gel-type strong cation exchange resin) in a water-containing state was filled in a Teflon column having an inner diameter of 20 mm and a length of 500 mm. To replace the water with PM, DOWNOL ™ PM (PM) is run at 40 mL / min for 3 hours. Then, sampling is started while changing the flow rate.

Comparative Example 2: Rinse the strong cation exchange resin floor MS650C UPW with PM flow.
After performing the test of "Comparative Example 1", the flow rate is reduced and the PM supply is continued at 2 BV / hour. After flowing at 2 BV / hour for 48 hours, the flow rate is increased to 16 BV / hour and a sample is taken.

The resin volume of Comparative Examples 1 and 2 shrinks to about 100 mL in a solvated state with PM.

Comparative Example 3: Weak cation exchange resin DOWNEX ™ MAC-3
A water-containing MAC-3 resin (gel-type weak cation exchange resin) was filled in a TEFLON column having an inner diameter of 20 mm and a length of 500 mm. After replacing the water with a PM stream of 16 BV / hour for 3 hours, a first PM sample is taken.

The resin volume expands from 120 ml in the water-containing state to 150 mL in the solvated state with PM.

Comparative Example 4: Dry mixed bed of strong cation exchange resin and MR type strong anion resin having high water retention capacity AMBERLYST ™ 31WET (gel type strong cation exchange resin) in a water-containing state of 40 ml and 80 ml of water-containing state Mix with AMBERJET ™ 9000 OH (MR type strong anion exchange resin). ΔTOC is measured at 12.8 ppb after running UPW for 2 hours at 25 BV / hour and 2.3 ppb after running for 24 hours.

The mixed resin is dried in a vacuum oven (60 ° C., 20 mmHg, 15 hours). After flowing PM at a flow rate of 16 BV / hour for 2 hours, a first sample is taken. Then, another sample is collected while changing the flow rate. The 120 mL hydrous resin volume shrinks to 96 mL in a solvated state with PM.

Comparative Example 5: A mixed bed of MR type strong cation exchange resin and MR type strong anion resin AMBERLITE 904Cl (MR type Cl ⁻ type strong cation exchange resin) is converted into OH type in the following manner.

500 mL of AMBERLITE ™ 904 Cl is filled into a stainless steel column 50 mm in diameter and 800 mm in length. 4% by weight caustic soda water soluble is heated in a temperature controlled tank at 60 ° C. A heated 4% caustic soda solution is run from the top of the column at 10 BV / hour for 2 hours to convert the chlorine form to the hydroxyl form. Rinsing with UPW flow is then performed at room temperature for 2 hours at 10 BV / hour. The resin collected from the column is a water-containing OH-converted anion exchange resin.

Construct a mixed floor in the following style.
40 ml of hydrous AMBERLYST ™ 15 WET (MR type H type strong cation exchange resin) and 80 ml of OH-converted AMBERLITE ™ 904 Cl in a hydrous state are uniformly mixed. The mixing ratio of the cation exchange resin and the anion exchange resin based on the above volume is 1: 1 in the equivalent ratio. The ΔTOC of the water-containing mixed resin is measured as 98 ppb after flowing UPW for 2 hours at a flow rate of 25 BV / hour and 30 ppb after flowing for 24 hours.

The mixed resin is dried in a vacuum oven (60 ° C., 20 mmHg) for 15 hours. The dried mixed resin is filled in a Teflon column having an inner diameter of 20 mm and a length of 500 mm. PM is flowed at a flow rate of 16 BV / hour for 2 hours. The 120 mL hydrous resin volume shrinks to 108 mL in a solvated state with PM. Samples are taken while changing the flow rate.

Example 1: A mixed bed of a strong cation exchange resin MS650C UPW and a strong anion exchange resin AMBERJET (trademark) UP4000. An equivalent amount of a water-containing wet cation resin MS650C UPW and a water-containing wet anion resin AMBERJET (trademark) UP4000. The ratio is 1: 1 and the mixture is mixed in a weight ratio of 39:61. ΔTOC is measured at 8.2 ppb after running UPW for 2 hours at 25 BV / hour and 0.7 ppb after running UPW for 24 hours. The metal content based on the dry resin in the mixed resin is 0.13 mg / Kg for Na, 0.12 mg / Kg for Al, 0.17 mg / Kg for Ca, 1.44 mg / Kg for Fe, and 0.01 mg / Kg for Cu. Measured as Kg.

120 mL of mixed resin is filled in a Teflon column having an inner diameter of 20 mm and a length of 500 mm.
Run PM at 16 BV / hour for 3 hours, replace the water with PM, and then stop the flow overnight. The resin volume shrinks from 120 mL in the water-containing state to 114 mL in the solvated state with PM. Then, the first sample is taken after flowing at 16 BV / hour for 1 hour the next day. Collect other samples while changing the flow rate.

Example 2: Mixed resin AMBERLITE ™ UP6040 (dry resin)
The ΔTOC of the tested resin is measured to be 1.9 ppb after running UPW for 2 hours at 25 BV / hour and less than 0.1 ppb after running UPW for 24 hours.

120 ml of a water-containing state AMBERLITE ™ UP6040 (a constant ratio mixture of a 1: 1 strong cation exchange resin and a weak anion exchange resin) is dried at 20 mmHg for 15 hours at 105 ° C. The metal content based on the dry resin in the mixed resin is 0.18 mg / Kg for Na, 0.12 mg / Kg for Al, 0.18 mg / Kg for Ca, 3.42 mg / Kg for Fe, and 0.00 mg / Kg for Cu. It is measured as 0.02 mg / Kg for Kg and Zn.

The Teflon column is filled with dry resin, PM is allowed to flow at 16 BV / hour for 3 hours for solvation, and the flow is stopped overnight. The resin volume expands from 125 mL in the water-containing state to 131 mL in the solvated state with PM.

The first sample is taken the next day after running at 16 BV / hour for 1 hour. Collect other samples while changing the flow rate.

Analysis The concentration of metal in the solvent sample was analyzed by ICP-MS (inductively coupled plasma mass spectrometry), and the analysis results are shown in Tables 1-6. The original metal level (concentration) and metal element ratio vary depending on the feed solvent lot.

The concentration of 1-methoxy-2-propanol (main component in PM) was evaluated by GC-FID (gas chromatography with flame ionization detector), and the results are shown in Tables 1-6. The definition of purity is the area% of 1-methoxy-2 propanol.

Claims (9)

A method for removing ionic contaminants from a hydrophilic organic solvent containing ether, wherein the method is:
Including contacting the hydrophilic organic solvent with a mixed bed of an ion exchange resin containing a cationic ion exchange resin and an anionic ion exchange resin.
(A) The cationic ion exchange resin is a hydrogen (H) type strong acid cationic ion exchange resin having a water retention capacity of 40 to 55% by weight.
(B) Both the cationic ion exchange resin and the anionic ion exchange resin ^{have a porosity of 0.001 to 0.1 cm 3} / g, an average pore size of 0.001 to 1.7 nm, and 0. A method having a BET surface area of 001 to 10 m ^{2 / g.} The mixed bed of the ion exchange resin is described by the following method:
The mixed bed of the ion exchange resin is washed with 25 bed volumes (BV) of ultrapure water for 24 hours, and then the total organic carbon of the ultrapure water is analyzed. The method according to claim 1. The contents of Na, K, Ca, Al, Fe, Ni, Zn, Cu, Cr, and Sn in the H-type strongly cationic ion exchange resin and the anionic ion exchange resin are the ion exchanges, respectively. The method according to claim 1 or 2 , wherein the dry weight of the resin is 10 mg / kg or less as a reference. The concentrations of Na, K, Ca, Al, Fe, Ni, Zn, Cu, Cr, and Sn in the hydrophilic organic solvent after contact with the mixed bed of the ion exchange resin are 0.1 ppb or less, respectively. The hydrophilic organic solvent obtained by the method according to any one of claims 1 to 3. A method for removing ionic contaminants from hydrophilic organic solvents containing ethers.
(I) A step of preparing mixed bed ions of an exchange resin containing a hydrogen (H) type strongly cationic ion exchange resin and a strongly anionic ion exchange resin.
(A) The cationic ion exchange resin has a water retention capacity of 40 to 55% by weight.
(B) Both the cationic ion exchange resin and the anionic ion exchange resin ^{have a porosity of 0.001 to 0.1 cm 3} / g, an average pore size of 0.001 to 1.7 nm, and 0. With a step of preparation, having a BET surface area of 001 to 10 m ^{2 / g,}
(Ii) A method comprising contacting a hydrophilic organic solvent with the mixed bed of the ion exchange resin. The method further comprises rinsing (iii) the mixed bed of the ion exchange resin with the hydrophilic organic solvent in a volume of 30-50 bed volumes (BV) at a flow rate of 1-50 BV / hour, step (iii). The method of claim 5, performed between steps (i) and (ii). The method according to any one of claims 1 to 8, wherein the hydrophilic organic solvent is composed of ether. The method according to any one of claims 1 to 7, wherein the ether is propylene glycol mono-methyl ether, dipropylene glycol mono-methyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-butyl ether, or a mixture thereof. .. The method according to any one of claims 1 to 7, wherein the ether is propylene glycol mono-methyl ether.